MARCH 6, 2025 – The Defense Department and a team of interagency partners led by the FBI engaged in an iteration of the Prominent Hunt exercise to validate the team’s ability to gather evidence to support presidential decision-making during a nuclear attack scenario.
“The Prominent Hunt exercise series not only tests the U.S. government’s technical capabilities, it also serves as a mechanism to reinforce the soft skills of collaboration and teamwork among federal, state and local partners,” said Susan Ferensic, assistant director of the FBI’s Weapons of Mass Destruction Directorate.
Participants included the Department of Energy’s National Nuclear Security Administration, the FBI and DOD. In particular, from DOD was the Army’s 20th CBRNE Command and the Air Force Technical Application Center. Together these agencies make up the National Technical Nuclear Forensics Ground Collection Task Force.
Prominent Hunt took place Jan. 26-31, 2025, in the vicinity of Schenectady, New York, and in the surrounding counties of Albany and Saratoga.
In the event of a nuclear detonation, the ground collection task force is responsible for collecting nuclear ground debris samples near the site of the detonation and transporting those samples to DOD laboratories for analysis, said Brian Kohler, the director of Nuclear Forensics, Energy and Survivability within DOD’s Office of Nuclear Matters.
The results of that analysis, coupled with input from the intelligence community, allows the U.S. government to discover who the responsible party for a detonation is.
“These technical skills and tools deny potential perpetrators — including state sponsors of terrorism — anonymity and ensure they will be held fully accountable. Prominent Hunt exercises are key to demonstrating these capabilities,” said Wendin Smith, NNSA associate administrator and deputy undersecretary for counterterrorism and counterproliferation.
The U.S. publicly demonstrating its ability to uncover responsible parties to hold them accountable has a deterrent effect, Kohler said. It’s not just about finding guilty parties after an attack; it’s about letting adversaries know in advance they will be found out.
“National technical nuclear forensics is absolutely a part of nuclear deterrence by messaging to our adversaries that the United States government has the capability, should there be a nuclear detonation,” Kohler said.
Explosions
Nuclear forensics was mandated by Congress in the early 2000s as a response to the 9/11 terrorist attacks. One of the goals was to enhance the ability to use forensic evidence from the nuclear debris to discover who was responsible for a nuclear detonation inside the contiguous U.S. But those explosions that Prominent Hunt focuses on are not from nuclear missiles like those that might come from a nuclear-armed adversary nation.
When people think of nuclear detonations, their first thought is ballistic missiles and bomber aircraft, said Timothy Jacomb-Hood, the senior scientific advisor for the Office of Nuclear Matters. However, nuclear forensics is focused on deterring attacks by terrorists using an improvised nuclear device or by states who plan to deny responsibility for an attack. These types of attacks won’t be traceable from a launch within a nation.
If a nuclear detonation occurs in a city, the ground collection task force is going to be essential to understand where it came from and how it got there. Without on-the-ground evidence collection, it’s more difficult to identify the perpetrator of those types of detonations, Jacomb-Hood said.
“In those scenarios, you’re less certain, and you need to know with total confidence who was responsible for this attack so that we can inform our senior leaders, and they can determine the appropriate response,” he added.
In addition to using forensics to uncover perpetrators of a nuclear detonation, nuclear forensics is also used to determine the origin of interdicted or recovered nuclear or radiological materials or devices that have been lost, stolen or smuggled.
Radiological Fingerprints
After such a detonation, the ground collection task force sets to work collecting evidence needed to help find those responsible. In particular, Jacomb-Hood said that what they are looking for is radioactive debris that can be analyzed. The unique signatures of the uranium or the plutonium can help determine what nation created it.
“We’re looking for those radiological fingerprints, those things that are unique to different countries, to be able to point back to where the nuclear weapon came from,” he said.
In some cases, he said, it’s easier to identify that some radiological material could not have come from a particular nation. Even eliminating potential nations enables the intelligence community to be more successful in determining where radiological material did come from.
To gather radiological evidence, the ground collection task force must know where to look for it. Part of the team’s capability is predicting the best place to look for evidence.
“When a nuclear detonation occurs, you see the traditional mushroom cloud. And in that cloud are the debris that we want to collect,” Jacomb-Hood said. “But we need to do various models of the detonation and the local weather to determine where the best debris [is] going to fall.”
That effort involves gathering information about where the explosive device was when it was detonated, how big of a yield it was, and then comparing that with weather models to find wind direction and wind speed so that a determination can be made about the best place to collect debris, he said.
“[The Air Force Technical Applications Center] is using that to know where to send the 20th CBRNE collectors,” Jacomb-Hood said. “They’re going to multiple locations to get a range of different samples that are then used, back at the labs, to determine through various scientific processes what the original device was.”
It’s not just ground collection of radiological evidence that happens, there are other avenues as well, he said. In a real-world situation, the Air Force also collects airborne debris using aircraft, and there also is input from satellite data.
“We’re going to fuse all of that data together, all that scientific data and then combine that with intelligence data and put all of these different puzzle pieces together to give our senior leaders an assessment of [who] perpetrated this attack,” he said.
Success
In this most recent iteration of Prominent Hunt, Drew Walter, deputy assistant secretary of defense for nuclear matters, said the ground collection task force accomplished their goal successfully and was validated.
“The National Technical Nuclear Forensics program recently validated the ground collection task force during Prominent Hunt. Our DOD team demonstrated their readiness to collect forensics-quality debris samples, working with their FBI and NNSA partners. Our ability to gather post-detonation debris and perform nuclear forensics analysis is a key element of our nuclear deterrent. Through NTNF, our senior leaders are provided a confident assessment of the responsible actor, ensuring appropriate response options,” Walter said.
In the coming weeks, Kohler said, the department will also produce and publish an after-action review of the exercise.
In August, Kohler said, there will be another iteration of Prominent Hunt. The exercise occurs about every six months so that the teams performing the ground collection stay sharp, and the interagency partnership is a well-oiled machine.
The Defense Threat Reduction Agency’s exercise division was brought on board to assist in exercise planning, Kohler said. Going forward, DTRA will have a larger role in this portion, which will allow the Office of Nuclear Matters to focus more on oversight and guidance.
By C. Todd Lopez, DOD News